Display Device Including Light Emitting Diode and Method of Fabricating the Same

The present application claims the priority of Republic of Korea Patent Application No. 10-2024-0174495 filed on Nov. 29, 2024, which is hereby incorporated by reference in its entirety.

The present disclosure relates to a display device, and more particularly, to a display device including a light emitting diode having a mesa region of different depths and areas.

Recently, various flat panel display devices such as a liquid crystal display device (LCD), an organic light emitting diode (OLED) display device and a field emission display (FED) device having excellent properties of a thin profile, a light weight and a low power consumption have been developed and applied to various fields.

Although the OLED display device among the various flat panel display devices has an advantage such that an additional light source is not required, the OLED display device has a disadvantage such that deterioration may occur by an external circumstance due to a property of an organic material vulnerable to moisture and oxygen.

To overcome the disadvantage, a display device using a light emitting diode chip (or a light emitting diode) of an inorganic material has been suggested.

The light emitting diode chip is attached to a display panel after the light emitting diode chip is formed on a growth substrate. To distinguish red, green, and blue light emitting diode chips from each other, the red, green, and blue light emitting diode chips are formed to have elliptical shapes having different long axes and different short axes.

As a resolution increases, a size of the light emitting diode chip decreases. As a result, an exclusivity according to a long axis and a short axis of the light emitting diode chip may be reduced, and the light emitting diode may be broken.

Accordingly, the present disclosure is directed to a display device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

More specifically, the present disclosure provides a display device including a light emitting diode where a color mixture is prevented or at least reduced and a fabrication process is optimized by changing a depth or an area of a mesa region.

Further, the present disclosure is to provide a display device including a light emitting diode applicable to a high resolution by forming a mesa region with different depths or different areas and a method of fabricating the display device.

Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the disclosure. These and other advantages of the disclosure will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purpose of the present disclosure, as embodied and broadly described herein, a display device includes: a display panel; a plurality of gate lines and a plurality of data lines in the display panel, the plurality of gate lines and the plurality of data lines crossing each other to define first, second and third subpixels; a transistor in each of the first, second and third subpixels and connected to the plurality of gate lines and the plurality of data lines; and first, second and third light emitting diodes in the first, second and third subpixels, respectively, and connected to the transistor, wherein a top surface of each of the first, second and third light emitting diodes includes a first surface under a step difference in a cross-sectional view and a second surface over the step difference in a cross-sectional view, and wherein the first surfaces of the first, second and third light emitting diodes have one of depths different from each other and areas different from each other.

In another embodiment, a method of fabricating a display device includes: assembling first, second and third light emitting diodes in first, second and third assembly grooves, respectively, of an assembly substrate; and transferring the first, second and third light emitting diodes to a display panel by disposing the assembly substrate having the first, second and third light emitting diodes over the display panel, wherein a top surface of each of the first, second and third light emitting diodes includes a first surface under a step difference in a cross-sectional view and a second surface over the step difference in a cross-sectional view, wherein the first surfaces of the first, second and third light emitting diodes have one of depths different from each other and areas different from each other, and wherein the first, second and third assembly grooves have first, second and third protruding portions, respectively, corresponding to the first surfaces of the first, second and third light emitting diodes

It is to be understood that both the foregoing general description and the following detailed description are explanatory and are intended to provide further explanation of the disclosure as claimed.

Advantages and features of the present disclosure, and implementation methods thereof will be clarified through following example aspects described with reference to the accompanying drawings. The present disclosure may, however, be embodied in different forms and should not be construed as limited to the example aspects set forth herein. Rather, these example aspects are provided so that this disclosure may be sufficiently thorough and complete to assist those skilled in the art to fully understand the scope of the present disclosure. Further, the present disclosure is only defined by scopes of claims.

The shapes, sizes, ratios, angles, numbers, and the like, which are illustrated in the drawings to describe various example aspects of the present disclosure, are merely given by way of example. Therefore, the present disclosure is not limited to the illustrations in the drawings. Like reference numerals refer to like elements throughout the specification, unless otherwise specified.

In the following description, where the detailed description of the relevant known function or configuration may unnecessarily obscure a feature or aspect of the present disclosure, a detailed description of such known function or configuration may be omitted or a brief description may be provided.

Where the terms “comprise,” “have,” “include,” and the like are used, one or more other elements may be added unless the term, such as “only,” is used. An element described in the singular form is intended to include a plurality of elements, and vice versa, unless the context clearly indicates otherwise.

In construing an element, the element is to be construed as including an error or a tolerance range even where no explicit description of such an error or tolerance range is provided.

Where positional relationships are described, for example, where the positional relationship between two parts is described using “on,” “over,” “under,” “above,” “below,” “beside,” “next,” or the like, one or more other parts may be located between the two parts unless a more limiting term, such as “immediate(ly),” “direct(ly),” or “close(ly)” is used. For example, where an element or layer is disposed “on” another element or layer, a third layer or element may be interposed therebetween.

Although the terms “first,” “second,” A, B, (a), (b), and the like may be used herein to refer to various elements, these elements should not be interpreted to be limited by these terms as they are not used to define a particular order or precedence. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure.

The term “at least one” should be understood to include all combinations of one or more of related elements. For example, the term of “at least one of first, second and third elements” may include all combinations of two or more of the first, second and third elements as well as the first, second or third element.

The term “display device” may include a display device in a narrow sense such as liquid crystal module (LCM), an organic light emitting diode (OLED) module and a quantum dot (QD) module including a display panel and a driving unit for driving the display panel. In addition, the term “display device” may include a complete product (or a final product) including the LCM, the OLED module and the QD module such as a notebook computer, a television, a computer monitor, an equipment display device including an automotive display apparatus or a shape other than a vehicle, and a set electronic apparatus or a set device (or a set apparatus) such as a mobile electronic apparatus of a smart phone or an electronic pad.

Accordingly, a display device of the present disclosure may include an applied product or a set device of a final user's device including the LCM, the OLED module and the QD module as well as a display device in a narrow sense such as the LCM, the OLED module and the QD module.

According to circumstances, the LCM, the OLED module, and the QD module having a display panel and a driving unit may be expressed as “a display device”, and an electronic apparatus of a complete product including the LCM, the OLED module and the QD module may be expressed as “a set device.” For example, a display device in a narrow sense may include a display panel of a liquid crystal, an organic light emitting diode and a quantum dot and a source printed circuit board (PCB) of a control unit for driving the display panel, and a set device may further include a set PCB of a set control unit electrically connected to the source PCB for controlling the entire set device.

The display panel of the present disclosure may include all kinds of display panels such as a liquid crystal display panel, an organic light emitting diode display panel, a quantum dot display panel and an electroluminescent display panel. The display panel of the present disclosure is not limited to a specific display panel of a bezel bending having a flexible substrate for an organic light emitting diode display panel and a lower back plate supporter. A shape or a size of the display panel for the display device of the present disclosure is not limited thereto.

For example, when the display panel is an organic light emitting diode display panel, the display panel may include a plurality of gate lines, a plurality of data lines and a subpixel in a crossing region of the plurality of gate lines and the plurality of data lines. The display panel may include an array having a thin film transistor of an element for selectively applying a voltage to each subpixel, an emitting element layer on the array and an encapsulating substrate or an encapsulation part covering the emitting element layer. The encapsulation part may protect the thin film transistor and the emitting element layer from an external impact and may prevent or at least reduce penetration of a moisture or oxygen into the emitting element layer. In addition, the emitting element layer on the array may include an inorganic light emitting layer, for example, a nano-sized material layer or a quantum dot.

The thin film transistor of the present disclosure may include one of an oxide thin film transistor, an amorphous silicon thin film transistor, and a low temperature polycrystalline silicon thin film transistor.

Features of various embodiments of the present disclosure may be partially or entirely coupled to or combined with each other. They may be linked and operated technically in various ways as those skilled in the art may sufficiently understand. The aspects may be carried out independently of or in association with each other in various combinations.

Hereinafter, a display device according to various example embodiments of the present disclosure where an influence on an oxide semiconductor layer of a thin film transistor of a driving element part is reduced by shielding a light emitted and transmitted from a subpixel and/or a light inputted from an exterior will be described in detail with reference to the accompanying drawings.

1 FIG. is a view showing a display device according to a first embodiment of the present disclosure. Although the display device may be an organic light emitting diode (OLED) display device, it is not limited thereto. For example, the display device may be a micro light emitting diode (LED) display device or a mini light emitting diode (LED) display device.

1 FIG. 110 120 122 124 126 128 In, a display deviceaccording to a first embodiment of the present disclosure includes a timing controlling unit(e.g., a circuit), a data driving unit(e.g., a circuit), first and second gate driving unitsand(e.g., circuits) and a display panel.

120 120 122 124 126 The timing controlling unitgenerates image data RGB, a data control signal DCS and a gate control signal GCS using an image signal and a plurality of timing signals including a data enable signal, a horizontal synchronization signal, a vertical synchronization signal and a clock signal transmitted from an external system such as a graphic card or a television system. The timing controlling unittransmits the image data RGB and the data control signal DCS to the data driving unitand transmits the gate control signal GCS to the first and second gate driving unitsand.

122 120 128 2 FIG. The data driving unitgenerates a data signal (a data voltage) Vda (of) using the image data RGB and the data control signal DCS transmitted from the timing controlling unitand transmits the data signal Vda to a data line DL of the display panel.

124 126 120 128 2 FIG. The first and second gate driving unitsandgenerate a gate signal (a gate voltage) Vsc and Vse (of) using the gate control signal GCS transmitted from the timing controlling unitand applies the gate signal Vsc and Vse to a gate line GL of the display panel.

124 126 128 The first and second gate driving unitsandmay have a gate in panel (GIP) type to be formed in a non-display area NDA of a substrate of the display panelhaving the gate line GL, the data line DL and a pixel P.

124 126 128 128 1 FIG. Although the first and second gate driving unitsandare disposed in both side portions of the display panelin the first embodiment of, one gate driving unit may be disposed in one side portion of the display panelin another embodiment.

128 128 128 The display panelincludes a display area DA at a central portion thereof and a non-display area NDA surrounding the display area DA. The display paneldisplays an image using the gate signal Vsc and Vse and the data signal Vda. For displaying an image, the display panelincludes a plurality of pixels P, a plurality of gate lines GL and a plurality of data lines DL in the display area DA.

1 2 3 1 2 3 1 2 3 1 2 3 Each of the plurality of pixels P includes first, second and third subpixels SP, SPand SP, and the gate line GL and the data line DL cross each other to define the first, second and third subpixels SP, SPand SP. Each of the first, second, and third subpixels SP, SP, and SPis connected to the gate line GL and the data line DL. For example, the first, second and third subpixels SP, SPand SPmay correspond to first, second and third colors, respectively, and the first, second and third colors may be red, green and blue colors, respectively.

1 2 3 2 FIG. 2 FIG. 2 FIG. 2 FIG. 2 FIG. Each of the first, second, and third subpixels SP, SP, and SPmay include a plurality of transistors such as a switching transistor Tsw (of), a driving transistor Tdr (of) and a sensing transistor Tse (of), a storage capacitor Cst (of) and a light emitting diode Del (of).

2 FIG. is a circuit diagram showing a subpixel of a display device according to a first embodiment of the present disclosure.

2 FIG. 1 2 3 128 110 In, each of the first, second, and third subpixels SP, SP, and SPof the display panelof the display deviceaccording to a first embodiment of the present disclosure includes a switching transistor Tsw, a driving transistor Tdr, a sensing transistor Tse, a storage capacitor Cst, and a light emitting diode Del.

1 2 3 1 2 3 2 FIG. Although each of the first, second and third subpixels SP, SPand SPhas a 3T1C structure having three transistors and one storage capacitor in the first embodiment of, each of the first, second and third subpixels SP, SPand SPmay have one of a 6T1C structure having six transistors and one storage capacitor, a 7T1C structure having seven transistors and one storage capacitor and a 8T1C structure having eight transistors and one storage capacitor in another embodiment.

2 FIG. Although the switching transistor Tsw, the driving transistor Tdr and the sensing transistor Tse may have a negative type in the first embodiment of, at least one of the switching transistor Tsw, the driving transistor Tdr and the sensing transistor Tse may have a positive type in another embodiment.

1 The switching transistor Tsw is switched according to a scan signal Vsc to transmit a data signal Vda to a first node N.

1 A gate electrode of the switching transistor Tsw is connected to the gate line GL to receive the scan signal Vsc, a drain electrode of the switching transistor Tsw is connected to the data line DL to receive the data signal Vda, and a source electrode of the switching transistor Tsw is connected to the first node N.

1 2 The driving transistor Tdr is switched according to a voltage of the first node Nto transmit a high level signal (high level voltage) Vdd to a second node N.

1 2 A gate electrode of the driving transistor Tdr is connected to the first node N, a drain electrode of the driving transistor Tdr is connected to a high level power line to receive the high level signal Vdd, and a source electrode of the driving transistor Tdr is connected to the second node N.

2 3 The sensing transistor Tse is switched according to a sensing signal (sensing voltage) Vse to transmit a reference signal (reference voltage) Vre to the second node Nor transmit a voltage of the second node Nto a reference line.

2 2 A gate electrode of the sensing transistor Tse is connected to the gate line GL to receive the sensing signal Vse, a drain electrode of the sensing transistor Tse is connected to the reference line to receive the reference signal Vre or transmit a voltage of the second node Nto the reference line, and a source electrode of the sensing transistor Tse is connected to the second node N.

1 The storage capacitor Cst keeps the data signal Vdata supplied to the first node Nfor one frame and stores a threshold voltage Vth of the driving transistor Tdr.

1 2 A first capacitor electrode of the storage capacitor Cst is connected to the first node N, and a second capacitor electrode of the storage capacitor Cst is connected to the second node N.

The light emitting diode Del emits a light of a luminance proportional to a current of the driving transistor Tdr.

2 An anode of the light emitting diode Del is connected to the second node N, and a cathode of the light emitting diode Del is connected to a low level power line to receive a low level signal (low level voltage) Vss.

1 2 The source electrode of the switching transistor Tsw, the gate electrode of the driving transistor Tdr and the first capacitor electrode of the storage capacitor Cst constitute the first node N, and the source electrode of the driving transistor Tdr, the source electrode of the sensing transistor Tse, the second capacitor electrode of the storage capacitor Cst and anode of the light emitting diode Del constitute the second node N.

1 2 3 The light emitting diode Del may display an image having a luminance corresponding to the image data RGB according to a driving of subpixel circuits of the first, second and third subpixels SP, SPand SP.

1 2 3 128 110 A cross-sectional structure of each subpixel SP, SPand SPof the display panelof the display devicewill be illustrated with reference to a drawing.

3 FIG. is a cross-sectional view showing a subpixel of a display panel of a display device according to a first embodiment of the present disclosure.

3 FIG. 132 1 2 3 130 134 132 130 In, a light shielding patternis disposed in each of the first, second and third subpixels SP, SP, and SPon a substrate, and a first buffer layeris disposed on the light shielding patternover the entire substrate.

132 130 132 The light shielding patternmay block a light incident from a lower portion of the substrate. For example, the light shielding patternmay have a single layer or a multiple layer of a metallic material such as one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu) and an alloy thereof.

134 134 The first buffer layermay block a moisture or an oxygen permeating from an exterior. For example, the first buffer layermay have a single layer or a multiple layer of an inorganic insulating material such as silicon oxide (SiO2) and silicon nitride (SiNx).

136 134 132 138 136 130 A semiconductor layeris disposed on the first buffer layercorresponding to the light shielding pattern, and a gate insulating layeris disposed on the semiconductor layerover the entire substrate.

136 136 The semiconductor layerincludes a channel region not doped with an impurity at a central portion thereof and source and drain regions doped with an impurity at both side portions of the channel region. For example, the semiconductor layermay include a polycrystalline semiconductor material such as polycrystalline silicon or an oxide semiconductor material such as indium gallium zinc oxide (IGZO), zinc oxide (ZnO), tin oxide (SnO2), copper oxide (Cu2O), nickel oxide (NiO), indium tin zinc oxide (ITZO) and indium aluminum zinc oxide (IAZO).

138 For example, the gate insulating layermay have a single layer or a multiple layer of an inorganic insulating material such as silicon oxide (SiO2) and silicon nitride (SiNx).

140 138 136 142 140 138 144 140 142 A gate electrodeis disposed on the gate insulating layercorresponding to the channel region of the semiconductor layer, a first capacitor electrodeseparated from the gate electrodeis disposed on the gate insulating layer, and a first interlayer insulating layeris disposed on the gate electrodeand the first capacitor electrode.

140 142 140 142 The gate electrodeand the first capacitor electrodemay have the same layer and the same material as each other. For example, the gate electrodeand the first capacitor electrodemay have a single layer or a multiple layer of a metallic material such as one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu) and an alloy thereof.

144 For example, the first interlayer insulating layermay have a single layer or a multiple layer of an inorganic insulating material such as silicon oxide (SiO2) and silicon nitride (SiNx).

146 144 142 148 146 130 A second capacitor electrodeis disposed on the first interlayer insulating layercorresponding to the first capacitor electrode, and a second interlayer insulating layeris disposed on the second capacitor electrodeover the entire substrate.

146 For example, the second capacitor electrodemay have a single layer or a multiple layer of a metallic material such as one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu) and an alloy thereof.

148 For example, the second interlayer insulating layermay have a single layer or a multiple layer of an inorganic insulating material such as silicon oxide (SiO2) and silicon nitride (SiNx).

142 144 146 The first capacitor electrode, the first interlayer insulating layer, and the second capacitor electrodemay constitute the storage capacitor Cst.

150 152 148 154 150 152 130 A source electrodeand a drain electrodethat are spaced apart from each other are disposed on the second interlayer insulating layer, and a first planarizing layeris disposed on the source electrodeand the drain electrodeover the entire substrate.

150 152 136 148 144 138 152 132 148 144 138 134 The source electrodeand the drain electrodeare connected to the source region and the drain region, respectively, of the semiconductor layerthrough contact holes in the second interlayer insulating layer, the first interlayer insulating layerand the gate insulating layer, and the drain electrodeis connected to the light shielding patternthrough a contact hole in the second interlayer insulating layer, the first interlayer insulating layer, the gate insulating layerand the first buffer layer.

150 152 150 152 The source electrodeand the drain electrodemay have the same layer and the same material as each other. For example, the source electrodeand the drain electrodemay have a single layer or a multiple layer of a metallic material such as one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu) and an alloy thereof.

154 For example, the first planarizing layermay have a single layer or a multiple layer of an organic insulating material such as photoacryl and benzocyclobutene (BCB).

136 140 150 152 The semiconductor layer, the gate electrode, the source electrodeand the drain electrodemay constitute the driving transistor Tdr.

156 154 150 158 156 154 160 156 158 130 A connecting electrodeis disposed on the first planarizing layercorresponding to the source electrode, a power linespaced apart from the connecting electrodeis disposed on the first planarizing layer, and an adhesive layeris disposed on the connecting electrodeand the power lineover the entire substrate.

156 150 154 156 158 The connecting electrodeis connected to the source electrodethrough a contact hole in the first planarizing layer, and the connecting electrodeand the power linemay have the same layer and the same material as each other.

156 158 For example, the connecting electrodeand the power linemay have a single layer or a multiple layer of a metallic material such as one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu) and an alloy thereof.

158 For example, the power linemay supply the low level signal Vss.

162 160 156 164 166 170 162 168 162 A first semiconductor layeris disposed on the adhesive layercorresponding to the connecting electrode, an active layer, a second semiconductor layerand a second electrodeare sequentially disposed on a first side portion of the first semiconductor layer, and a first electrodeis disposed on a second side portion of the first semiconductor layer.

162 164 166 164 164 The first semiconductor layersupplies an electron to the active layer, the second semiconductor layersupplies a hole to the active layer, and the active layergenerates a light using an electron and a hole.

162 166 164 For example, the first semiconductor layermay include a negative type gallium nitride (n-GaN), the second semiconductor layermay include a positive type gallium nitride (p-GaN), and the active layermay include a multi quantum well (MQW).

168 170 For example, the first electrodemay be a cathode, and the second electrodemay be an anode.

162 164 166 168 170 The first semiconductor layer, the active layer, the second semiconductor layer, the first electrode, and the second electrodemay constitute the light emitting diode Del (or light emitting diode chip).

172 168 170 130 174 176 172 A second planarizing layeris disposed on the first and second electrodesandover the entire substrate, and first and second connecting linesandthat are spaced apart from each other are disposed on the second planarizing layercorresponding to the light emitting diode Del.

172 For example, the second planarizing layermay have a single layer or a multiple layer of an organic insulating material such as photoacryl and benzocyclobutene (BCB).

174 158 160 172 168 172 The first connecting lineis connected to the power linethrough a contact hole in the adhesive layerand the second planarizing layerand connected to the first electrodethrough a contact hole in the second planarizing layer.

176 156 160 172 170 172 The second connecting lineis connected to the connecting electrodethrough a contact hole in the adhesive layerand the second planarizing layerand connected to the second electrodethrough a contact hole in the second planarizing layer.

174 176 For example, the first and second connecting linesandmay include a metallic material such as one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd) and copper (Cu) or a transparent conductive material such as indium tin oxide (ITO) and indium zinc oxide (IZO).

174 176 172 168 170 172 172 168 174 168 174 168 176 168 In the first embodiment, the first and second connecting linesandare exemplarily disposed on the second planarizing layerto be connected to the first and second electrodesand, respectively, through the contact holes in the second planarizing layer. In another embodiment, after the second planarizing layermay be removed through an ashing step till the first electrodeis exposed, the first connecting lineconnected to the first electrodemay be formed and a third planarizing layer may be coated on the first connecting line. Next, after the third planarizing layer may be removed through an ashing step till the second electrodeis exposed, the second connecting lineconnected to the second electrodemay be formed.

178 174 176 130 An encapsulating layeris disposed on the first and second connecting linesandover the entire substrate.

178 The encapsulating layerprevents or at least reduces a permeation of a particle such as an oxygen or a moisture.

178 For example, the encapsulating layermay have a single layer or a multiple layer of an inorganic insulating material such as silicon oxide (SiO2) and silicon nitride (SiNx).

110 130 The light emitting diode Del of the display devicemay be attached to the substratethrough a self-assembly technology.

4 FIG. 5 FIG. 4 FIG. is a view showing an assembly substrate of a light emitting diode of a display device according to a first embodiment of the present disclosure, andis a magnified view of a portion A ofaccording to one embodiment.

4 FIG. 210 212 232 230 210 234 232 In, an assembly substratehaving a plurality of assembly groovesis disposed over a chamber, a magnetic rodgenerating a magnetic field is disposed over the assembly substrate, and a fluidincluding a plurality of light emitting diodes (LEDs) Del is disposed in the chamber.

230 The magnetic rodmay move along up, down, left and right directions and rotate, and the plurality of LEDs Del may be formed on a growth substrate and then be detached from the growth substrate.

234 For example, the fluidmay include a water such as a deionized water.

210 234 230 The plurality of LEDs Del moves toward the assembly substratein the fluidby the magnetic field of the magnetic rod, and each of the LEDs Del may have a magnetic layer.

162 166 168 170 For example, the magnetic layer may include a metal having a magnetic property such as nickel (Ni) and may be disposed on a top surface or a side surface of the first semiconductor layeror the second semiconductor layeror in at least one of first and second electrodesandof the LED Del.

5 FIG. 220 222 210 224 220 222 210 In, first and second assembly electrodesandspaced apart from each other are disposed on a lower surface of the assembly substrate, and an insulating layeris disposed on the first and second assembly electrodesandover the entire assembly substrate.

220 222 224 For example, the first and second assembly electrodesandmay include a transparent conductive material or a metallic material, and the insulating layermay have a single layer or a multiple layer of an inorganic insulating material or an organic insulating material.

226 224 220 222 226 220 222 212 212 A sidewallis disposed on the insulating layercorresponding to the first and second assembly electrodesand. The sidewallpartially overlaps each of the first and second assembly electrodesand, and a space surrounded by the sidewallconstitutes the assembly groove.

220 222 220 222 212 234 212 220 222 When an alternating current (AC) voltage is applied to the first and second assembly electrodesand, an electric field is generated between the first and second assembly electrodesand, and the LED Del adjacent to the plurality of assembly groovesamong the plurality of LEDs Del in the fluidmay be assembled to the assembly grooveby a dielectric phoretic force due to the electric field generated between the first and second assembly electrodesand.

210 1 168 2 170 212 The LED Del may be assembled to the assembly substratesuch that a first surface Shaving the first electrodeand a second surface Shaving the second electrodeface the assembly groove.

1 2 3 1 2 3 2 1 212 212 212 212 1 2 3 1 2 3 6 FIG.A 7 FIG.A 8 FIG.A 6 FIG.A 7 FIG.A 8 FIG.A 6 FIGS.A 7 FIGS.A 8 FIG.A a b c The plurality of LEDs Del include first, second, and third LEDs Del(of), Del(of) and Del(of) emitting first, second and third colored lights, respectively, and having first, second and third depths d(of), d(of) and d(of) from the second surface Sto the first surface S. The plurality of assembly groovesinclude first, second, and third assembly grooves(of),(of) and(of) corresponding to the first, second and third depths d, dand d, respectively, of the first, second and third LEDs Del, Deland Del.

For example, the first, second, and third colored lights may correspond to red, green, and blue light, respectively.

1 2 1 2 3 226 226 226 212 212 212 210 1 2 3 a b c a b c 6 FIGS.A 7 FIGS.A 8 FIG.A The first and second surfaces Sand Sof the first, second, and third LEDs Del, Deland Delare formed to have different depths, and first, second, and third protruding portions(of),(of) and(of) of the first, second, and third assembly grooves,andof the assembly substrateare formed to have different thicknesses. As a result, a distinguishability (exclusivity) between the first, second and third LEDs Del, Deland Delis obtained.

1 2 3 212 212 212 1 2 3 220 222 1 2 3 230 1 2 3 212 212 212 a b c a b c When the first, second and third LEDs Del, Deland Delare properly assembled to the first, second, and third assembly grooves,and, respectively, an electric force applied to the first, second, and third LEDs Del, Deland Delby the electric field of the first and second assembly electrodesandbecomes greater than a magnetic force applied to the first, second, and third LEDs Del, Deland Delby the magnetic field of the magnetic rodso that the first, second, and third LEDs Del, Deland Delcannot escape from and can be stably fixed to the first, second and third assembly grooves,and, respectively.

1 2 3 212 212 212 1 2 3 230 1 2 3 220 222 1 2 3 212 212 212 1 2 3 212 212 212 234 1 2 3 212 212 212 a b c a b c a b c a b c When the first, second, and third LEDs Del, Deland Delare not properly assembled to the first, second, and third assembly grooves,and, respectively, the magnetic force applied to the first, second and third LEDs Del, Deland Delby the magnetic field of the magnetic rodbecomes greater than the electric force applied to the first, second, and third LEDs Del, Deland Delby the electric field of the first and second assembly electrodesandso that the first, second, and third LEDs Del, Deland Delcan escape from the first, second, and third assembly grooves,and, respectively. The first, second, and third LEDs Del, Deland Delhaving escaped from the first, second, and third assembly grooves,andmay float in the fluidtill the first, second, and third LEDs Del, Deland Delare properly assembled to the first, second and third assembly grooves,and, respectively.

212 210 210 160 130 128 212 160 1 2 3 When the plurality of LEDs Del are properly assembled to the plurality of assembly groovesof the assembly substrate, the assembly substrateis disposed on the adhesive layerof the substrateof the display panel, and the plurality of LEDs Del of the plurality of assembly groovesare transferred and attached to the adhesive layerof each subpixel SP, SPand SPwithout using an additional transfer substrate.

130 210 In another embodiment, a transfer step may be omitted using the substratehaving the driving transistor Tdr as the assembly substrate.

210 Dispositions and shapes of the assembly substrateand the plurality of LEDs Del will be illustrated with reference to drawings.

6 FIG.A 6 FIG.B 6 FIG.C 7 FIG.A 7 FIG.B 7 FIG.C 8 FIG.A 8 FIG.B 8 FIG.C is a cross-sectional view showing a first assembly groove of an assembly substrate and a first light emitting diode for a display device according to a first embodiment of the present disclosure,is a cross-sectional view showing a first assembly groove of an assembly substrate and a second light emitting diode for a display device according to a first embodiment of the present disclosure, andis a cross-sectional view showing a first assembly groove of an assembly substrate and a third light emitting diode for a display device according to a first embodiment of the present disclosure.is a cross-sectional view showing a second assembly groove of an assembly substrate and a second light emitting diode for a display device according to a first embodiment of the present disclosure,is a cross-sectional view showing a second assembly groove of an assembly substrate and a first light emitting diode for a display device according to a first embodiment of the present disclosure, andis a cross-sectional view showing a second assembly groove of an assembly substrate and a third light emitting diode for a display device according to a first embodiment of the present disclosure.is a cross-sectional view showing a third assembly groove of an assembly substrate and a third light emitting diode for a display device according to a first embodiment of the present disclosure,is a cross-sectional view showing a third assembly groove of an assembly substrate and a first light emitting diode for a display device according to a first embodiment of the present disclosure, andis a cross-sectional view showing a third assembly groove of an assembly substrate and a second light emitting diode for a display device according to a first embodiment of the present disclosure.

220 222 224 210 6 8 FIGS.A toC For illustration's convenience, the first and second assembly electrodesandand the insulating layerof the assembly substrateare omitted in.

6 FIG.A 1 1 110 1 168 2 170 1 In, a top surface of the first LED Delin the first subpixel SPof the display deviceaccording to a first embodiment of the present disclosure includes the first surface S, referred to as a mesa region, having the first electrodeand the second surface Shaving the second electrodeand disposed higher than the first surface S.

212 210 226 1 2 226 212 226 1 2 1 a a a The first assembly grooveof the assembly substrateis defined as a space surrounded by the sidewalland has a shape corresponding to the first and second surfaces Sand S. The sidewallof the first assembly groovehas the first protruding portionextending from an inner surface thereof and corresponding to a step difference between the first and second surfaces Sand Sof the first LED Del.

1 1 1 2 1 1 2 1 The first LED Delhas one of a polygon shape, an ellipse shape, or a circle shape in a plan view. The first surface Sof the first LED Delis disposed under the step difference in a cross-sectional view, and the second surface Sof the first LED Delis disposed over the step difference in a cross-sectional view. The first and second surfaces Sand Shave the step difference of the first depth d.

226 212 1 1 a a The first protruding portionprotruding toward the first assembly groovehas a first thickness tsubstantially the same as the first depth d.

1 212 a. As a result, the first LED Delis stably assembled to the first assembly groove

7 FIG.A 2 2 110 1 168 2 170 1 In, a top surface of the second LED Delin the second subpixel SPof the display deviceaccording to a first embodiment of the present disclosure includes the first surface S, referred to as a mesa region, having the first electrodeand the second surface Shaving the second electrodeand disposed higher than the first surface S.

212 210 226 1 2 226 212 226 1 2 2 b b b The second assembly grooveof the assembly substrateis defined as a space surrounded by the sidewalland has a shape corresponding to the first and second surfaces Sand S. The sidewallof the second assembly groovehas the second protruding portionextending from an inner surface thereof and corresponding to a step difference between the first and second surfaces Sand Sof the second LED Del.

2 1 2 2 2 1 2 2 1 The second LED Delhas one of a polygon shape, an ellipse shape, or a circle shape in a plan view. The first surface Sof the second LED Delis disposed under the step difference in a cross-sectional view, and the second surface Sof the second LED Delis disposed over the step difference in a cross-sectional view. The first and second surfaces Sand Shave the step difference of the second depth dgreater than the first depth d.

226 212 2 2 b b The second protruding portionprotruding toward the second assembly groovehas a second thickness tsubstantially the same as the second depth d.

2 212 b. As a result, the second LED Delis stably assembled to the second assembly groove

8 FIG.A 3 3 110 1 168 2 170 1 In, a top surface of the third LED Delin the third subpixel SPof the display deviceaccording to a first embodiment of the present disclosure includes the first surface S, referred to as a mesa region, having the first electrodeand the second surface Shaving the second electrodeand disposed higher than the first surface S.

212 210 226 1 2 226 212 226 1 2 3 c c c The third assembly grooveof the assembly substrateis defined as a space surrounded by the sidewalland has a shape corresponding to the first and second surfaces Sand S. The sidewallof the third assembly groovehas the third protruding portionextending from an inner surface thereof and corresponding to a step difference between the first and second surfaces Sand Sof the third LED Del.

3 1 3 2 3 1 2 3 2 The third LED Delhas one of a polygon shape, an ellipse shape, or a circle shape in a plan view. The first surface Sof the third LED Delis disposed under the step difference in a cross-sectional view, and the second surface Sof the third LED Delis disposed over the step difference in a cross-sectional view. The first and second surfaces Sand Shave the step difference of the third depth dgreater than the second depth d.

226 212 3 3 c c The third protruding portionprotruding toward the third assembly groovehas a third thickness tsubstantially the same as the third depth d.

3 212 c. As a result, the third LED Delis stably assembled to the third assembly groove

6 6 FIGS.B andC 2 3 2 3 1 212 212 2 3 212 a a a. In, when the second and third LEDs Deland Delhaving the second and third depths dand dgreater than the first thickness tof the first assembly grooveare inserted into the first assembly groove, the magnetic force becomes greater than the electric force due to an abnormal assembly. As a result, the second and third LEDs Deland Delare not assembled to and easily escape from the first assembly groove

7 FIG.B 1 1 2 212 212 1 212 1 212 b b b b. In, when the first LED Delhaving the first depth dthat is smaller than the second thickness tof the second assembly grooveis inserted into the second assembly groove, the first LED Deldoes not contact the second assembly groovedue to the step difference. As a result, the first LED Delis not assembled to and easily escapes from the second assembly groove

7 FIG.C 3 3 2 212 212 3 212 b b b In, when the third LED Delhaving the third depth dthat is greater than the second thickness tof the second assembly grooveis inserted into the second assembly groove, the magnetic force becomes greater than the electric force due to an abnormal assembly. As a result, the third LED Delis not assembled to and easily escapes from the second assembly groove.

8 8 FIGS.B andC 1 2 1 2 3 212 212 1 2 212 1 2 212 c c c c. In, when the first and second LEDs Deland Delhaving the first and second depths dand dthat are smaller than the third thickness tof the third assembly grooveare inserted into the third assembly groove, the first and second LEDs Deland Deldo not contact the third assembly groovedue to the step difference. As a result, the first and second LEDs Deland Delare not assembled to and easily escape from the third assembly groove

226 1 2 3 In the first embodiment, when a dry etching step has a process margin of about ±5%, the dry etching step for forming the sidewallof a thickness of about 5 μm has a first process margin of about ±0.25 μm, and the dry etching step for forming the mesa region of the LED Del of the depth of about 2 μm has a second process margin of about ±0.1 μm. Accordingly, the first, second and third depths d, d, and dfor a sequential color mixture assembly of the LEDs Del may be determined to have a difference equal to or greater than about 0.35 μm, which is a sum of the first and second process margins.

1 2 3 For example, the first, second and third depths d, d, and dmay be about 1.5 μm, about 2.0 μm and about 2.5 μm, respectively.

110 1 1 2 3 1 2 3 226 226 226 212 212 212 1 2 3 1 2 3 1 2 3 1 2 3 a b c a b c In the display deviceaccording to a first embodiment of the present disclosure, the first surfaces (mesa region) Sof the first, second and third LEDs Del, Deland Delare formed to have the first, second and third depths d, dand ddifferent from each other, and the first, second and third protruding portions,andof the first, second and third assembly grooves,andare formed to have the first, second and third thicknesses t, tand tdifferent from each other and corresponding to the first, second and third depths d, dand d. As a result, an exclusivity (distinguishability) between the first, second and third LEDs Del, Deland Delis improved, and a color mixture due to an abnormal assembly of the first, second and third LEDs Del, Del, and Delis prevented to obtain a high resolution.

1 2 3 Although the first, second and third colors of the first, second, and third LEDs Del, Del, and Delexemplarily correspond to red, green, and blue, respectively, in the first embodiment, the first, second, and third colors may correspond to green, blue, and red, respectively, or blue, red, and green, respectively, in another embodiment. Alternatively, the first, second and third colors may correspond to different three colors, respectively, in another embodiment.

1 2 3 In another embodiment, the mesa regions of the first, second and third colors of the first, second and third LEDs Del, Deland Delmay have different areas.

9 FIG.A 9 FIG.B 9 FIG.C 9 FIG.D 10 FIG.A 10 FIG.B 10 FIG.C 10 FIG.D 11 FIG.A 11 FIG.B 11 FIG.C 11 FIG.D is a perspective view showing a first assembly groove of an assembly substrate and a first light emitting diode for a display device according to a second embodiment of the present disclosure,is a plan view showing a first assembly groove of an assembly substrate and a first light emitting diode for a display device according to a second embodiment of the present disclosure,is a plan view showing a first assembly groove of an assembly substrate and a second light emitting diode for a display device according to a second embodiment of the present disclosure, andis a plan view showing a first assembly groove of an assembly substrate and a third light emitting diode for a display device according to a second embodiment of the present disclosure.is a perspective view showing a second assembly groove of an assembly substrate and a second light emitting diode for a display device according to a second embodiment of the present disclosure,is a plan view showing a second assembly groove of an assembly substrate and a second light emitting diode for a display device according to a second embodiment of the present disclosure,is a plan view showing a second assembly groove of an assembly substrate and a first light emitting diode for a display device according to a second embodiment of the present disclosure, andis a plan view showing a second assembly groove of an assembly substrate and a third light emitting diode for a display device according to a second embodiment of the present disclosure.is a perspective view showing a third assembly groove of an assembly substrate and a third light emitting diode for a display device according to a second embodiment of the present disclosure,is a plan view showing a third assembly groove of an assembly substrate and a third light emitting diode for a display device according to a second embodiment of the present disclosure,is a plan view showing a third assembly groove of an assembly substrate and a first light emitting diode for a display device according to a second embodiment of the present disclosure, andis a plan view showing a third assembly groove of an assembly substrate and a second light emitting diode for a display device according to a second embodiment of the present disclosure.

220 222 224 210 9 11 FIGS.A toD For illustration's convenience, the first and second assembly electrodesandand the insulating layerof the assembly substrateare omitted in.

9 9 FIGS.A andB 1 1 168 2 170 1 In, a top surface of a first LED Delin a first subpixel of a display device according to a second embodiment of the present disclosure includes a first surface S, referred to as a mesa region, having a first electrodeand a second surface Shaving a second electrodeand disposed higher than the first surface S.

212 210 226 1 2 1 226 212 226 1 1 2 1 a a a A first assembly grooveof the assembly substrateis defined as a space surrounded by a sidewalland has a shape corresponding to the first and second surfaces Sand Sof the first LED Del. The sidewallof the first assembly groovehas a first protruding portionextending from an inner surface thereof and corresponding to the first surface Sand a step difference between the first and second surfaces Sand Sof the first LED Del.

1 1 1 2 1 1 1 1 The first LED Delhas a circle shape in a plan view. The first surface Sof the first LED Delis disposed under the step difference in a cross-sectional view and has a fan (circular sector) shape in a plan view. The second surface Sof the first LED Delis disposed over the step difference in a cross-sectional view. The first surface Sof a fan shape has a first central angle aand a first area A.

1 In another embodiment, the first LED Delmay have a polygon shape or an ellipse shape in a plan view.

226 212 1 1 a a The first protruding portionprotruding toward the first assembly groovehas a fan shape of the first central angle aand the first area A.

1 212 a. As a result, the first LED Delis stably assembled to the first assembly groove

10 10 FIGS.A andB 2 1 168 2 170 1 In, a top surface of a second LED Delin a second subpixel of a display device according to a second embodiment of the present disclosure includes a first surface S, referred to as a mesa region, having a first electrodeand a second surface Shaving a second electrodeand disposed higher than the first surface S.

212 210 226 1 2 2 226 212 226 1 1 2 2 b b b A second assembly grooveof the assembly substrateis defined as a space surrounded by a sidewalland has a shape corresponding to the first and second surfaces Sand Sof the second LED Del. The sidewallof the second assembly groovehas a second protruding portionextending from an inner surface thereof and corresponding to the first surface Sand a step difference between the first and second surfaces Sand Sof the second LED Del.

2 1 2 2 2 1 2 1 2 1 The second LED Delhas a circle shape in a plan view. The first surface Sof the second LED Delis disposed under the step difference in a cross-sectional view and has a fan (circular sector) shape in a plan view. The second surface Sof the second LED Delis disposed over the step difference in a cross-sectional view. The first surface Sof a fan shape has a second central angle agreater than the first central angle aand a second area Agreater than the first area A.

2 In another embodiment, the second LED Delmay have a polygon shape or an ellipse shape in a plan view.

226 212 2 2 b b The second protruding portionprotruding toward the second assembly groovehas a fan shape of the second central angle aand the second area A.

2 212 b. As a result, the second LED Delis stably assembled to the second assembly groove

11 11 FIGS.A andB 3 1 168 2 170 1 In, a top surface of a third LED Delin a third subpixel of a display device according to a second embodiment of the present disclosure includes a first surface S, referred to as a mesa region, having a first electrodeand a second surface Shaving a second electrodeand disposed higher than the first surface S.

212 210 226 1 2 3 226 212 226 1 1 2 3 c c c A third assembly grooveof the assembly substrateis defined as a space surrounded by a sidewalland has a shape corresponding to the first and second surfaces Sand Sof the third LED Del. The sidewallof the third assembly groovehas a third protruding portionextending from an inner surface thereof and corresponding to the first surface Sand a step difference between the first and second surfaces Sand Sof the third LED Del.

3 1 3 2 3 1 3 2 3 2 The third LED Delhas a circle shape in a plan view. The first surface Sof the third LED Delis disposed under the step difference in a cross-sectional view and has a fan (circular sector) shape in a plan view. The second surface Sof the third LED Delis disposed over the step difference in a cross-sectional view. The first surface Sof a fan shape has a third central angle agreater than the second central angle aand a third area Agreater than the second area A.

3 In another embodiment, the third LED Delmay have a polygon shape or an ellipse shape in a plan view.

226 212 3 3 c c The third protruding portionprotruding toward the third assembly groovehas a fan shape of the third central angle aand the third area A.

3 212 c. As a result, the third LED Delis stably assembled to the third assembly groove

9 9 FIGS.C andD 2 3 2 3 1 226 2 3 1 226 212 2 3 212 a a a a. In, when the second and third LEDs Deland Delhaving the second and third central angles aand athat are greater than the first central angle aof the first protruding portionand having the second and third areas Aand Agreater than the first area Aof the first protruding portionare inserted into the first assembly groove, the magnetic force becomes greater than the electric force due to an abnormal assembly. As a result, the second and third LEDs Deland Delare not assembled to and easily escape from the first assembly groove

10 FIG.C 1 1 2 226 1 2 226 212 1 212 226 1 212 b b b b b b. In, when the first LED Delhaving the first central angle asmaller than the second central angle aof the second protruding portionand having the first area Asmaller than the second area Aof the second protruding portionis inserted into the second assembly groove, the first LED Deldoes not contact the second assembly groovedue to the second protruding portion. As a result, the first LED Delis not assembled to and easily escapes from the second assembly groove

10 FIG.D 3 3 2 226 3 2 226 212 3 212 b b b b. In, when the third LED Delhaving the third central angle agreater than the second central angle aof the second protruding portionand having the third area Agreater than the second area Aof the second protruding portionis inserted into the second assembly groove, the magnetic force becomes greater than the electric force due to an abnormal assembly. As a result, the third LED Delis not assembled to and easily escapes from the second assembly groove

11 11 FIGS.C andD 1 2 1 2 3 226 1 2 3 226 212 1 2 212 226 1 2 212 c c c c c c. In, when the first and second LEDs Deland Delhaving the first and second central angles aand asmaller than the third central angle aof the third protruding portionand having the first and second areas Aand Asmaller than the third area Aof the third protruding portionare inserted into the third assembly groove, the first and second LEDs Deland Deldo not contact the third assembly groovedue to the third protruding portion. As a result, the first and second LEDs Deland Delare not assembled to and easily escape from the third assembly groove

226 212 1 2 3 a In the second embodiment, since a dry etching step for forming the sidewallhaving the assembly grooveof a circle shape of a diameter of about 12 μm has a process margin of about ±2 μm with respect to one side of an arc, the first, second and third central angle a, a, and afor a sequential color mixture assembly of the LEDs Del may be determined to have a difference equal to or greater than about 19.1 degrees obtained by converting the process margin into an angle.

1 2 3 For example, the first, second and third central angles a, aand amay be about 50 degrees, about 90 degrees and about 130 degrees, respectively.

1 1 2 3 1 2 3 1 2 3 226 226 226 212 212 212 1 2 3 1 2 3 1 2 3 1 2 3 a b c a b c In the display device according to a second embodiment of the present disclosure, the first surfaces (mesa region) Sof the first, second and third LEDs Del, Deland Delare formed to have the first, second and third central angles a, aand adifferent from each other and the first, second and third areas A, Aand Adifferent from each other, and the first, second and third protruding portions,andof the first, second and third assembly grooves,andare formed to have the first, second and third central angles a, aand adifferent from each other and the first, second and third areas A, Aand Adifferent from each other. As a result, an exclusivity (distinguishability) between the first, second and third LEDs Del, Deland Delis improved, and a color mixture due to an abnormal assembly of the first, second and third LEDs Del, Deland Delis prevented to obtain a high resolution.

1 2 3 Although the first, second and third colors of the first, second and third LEDs Del, Deland Delexemplarily correspond to red, green and blue, respectively, in the second embodiment, the first, second and third colors may correspond to green, blue and red, respectively, or blue, red and green, respectively, in another embodiment. Alternatively, the first, second and third colors may correspond to different three colors, respectively, in another embodiment.

Consequently, in the display device according to the present disclosure, a color mixture is prevented or at least reduced and a fabrication process is optimized by changing a depth and an area of a mesa region. Further, a simultaneous assembly technology is applied to a relatively high resolution by forming the mesa regions of the red, green and blue light emitting diodes with the different depths or the different areas.

It will be apparent to those skilled in the art that various modifications and variation may be made in the present disclosure without departing from the scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.